ESA Assures Asteroid Didymos No Threat To Earth, Target Of Study Due To Ease Of Reach

The Didymos binary asteroid system to which the European Space Agency (ESA) Hera mission is heading for a six-month close-up study, was chosen because the space body is easy to reach and is an interesting and representative target, the Hera team at the ESA told Sputnik, adding that Didymos has "no collision probability" with our planet in the foreseeable future

MOSCOW (UrduPoint News / Sputnik - 26th October, 2020) The Didymos binary asteroid system to which the European Space Agency (ESA) Hera mission is heading for a six-month close-up study, was chosen because the space body is easy to reach and is an interesting and representative target, the Hera team at the ESA told Sputnik, adding that Didymos has "no collision probability" with our planet in the foreseeable future.

In September, the ESA signed a contract worth some $153 million, which covers the design, manufacturing and testing of the Hera mission with the OHB multinational technology corporation hardhearted in the German city of Bremen. The ambitious mission � named after the Greek goddess of marriage � is due to become the first-ever project in Earth's history to allow a rendezvous with a binary asteroid system, named Didymos, which is classified as a potentially hazardous asteroid. The whole project, which is scheduled to start in October 2024, is part of the international asteroid deflection effort, dubbed Asteroid Impact and Deflection Assessment (AIDA), which is being carried out jointly with NASA.

"Didymos was chosen, because it is a very interesting and representative target in many aspects and it is relatively easy to reach. In 2023 it will be close enough to illuminate it with radar from the ground (but still far enough away to be no danger at all, at ~0.45AU [astronomical unit])," ESA Science Operations Scientist Richard Moissl said.

Didymos, which is about half a mile in diameter, was discovered back in 1996. Nearly a decade later, in 2003, the scientists discovered its minor planet moon, dubbed Dimorphos, which is only 524 feet in diameter. The name, Didymos, which is translated from Greek as "twins," is also applied to the synchronous binary system that Didymos and Dimorphos make up.

According to Moissl, the diameter of Dimorphos is a size from which asteroids start becoming a threat to major population centers. ESA estimates that Dimorphos is the size of the Great Pyramid of Giza.

Prior to the ESA sending the Hera mission, NASA is due to send a Double Asteroid Redirection Test (DART) within the AIDA project. DART, which is expected to arrive at the double asteroid by Autumn 2022, when the Didymos system is about 6.8 miles from Earth. The DART spacecraft will deliberately crash itself into Dimorphos, changing the speed of the moonlet in its orbit around Didymos by a fraction of one percent.

Moissl said that the impact from the DART would not alter the orbit of the Didymos system around the sun.

"It is not intended to actively save us from an impact hazard but to learn what we need to know in order to actually do that one day. So far we have calculations that give us some idea of how to deflect asteroids, but we won't know for certain if we got it right until we have tried it for real," he explained.

Moissl added that since the mission is aiming for the smaller of two asteroids, the experiment "is absolutely safe.

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NASA views Dimorphos as the perfect target for DART because of its orbit around Didymos and the system's relatively close proximity to Earth in 2022.

DIDYMOS HAS 'NO COLLISION PROBABILITY' WITH EARTH IN FORSEEABLE FUTURE

According to Moissl, Didymos "has no collision probability with Earth for the foreseeable future," which means that it would be harmless for our planet for the next 100 years.

"This is one reason why Hera is going there, so we have a safe target to do our studies and learn everything we can in order to be prepared for deflecting an asteroid in the future. One benefit of the data we collect with Hera will actually be to understand better and more accurately how much in advance an asteroid needs to be deflected before it would impact earth," he explained.

Its composition seems to be rather typical for near earth asteroids, so it is quite a representative target that will provide us with useful information for a lot of other asteroids, he added.

DISTANCE ITSELF BEGGEST CHALLENGE

Hera will depart Earth in 2024 and will arrive on Didymos in 2027, some five years after the DART impact. For the record, in 2022, Didymos will come 7 million miles close to Earth. This means that Hera will have to cover millions of miles to reach the destination.

"The distance itself is the greatest challenge. It means that we do not see anything happen to Hera in real time, but with some delay," Moissl explained.

According to the scientist, the Hera team will also have to brace for other potential problems, including power failures, solar interference, the loss of communication or damage.

"For example, the spacecraft needs to be able to cope by itself with an unforeseen loss of communication (it will move in a safe search pattern and call for help from the earth until we answer). In addition, our spacecraft operators do a lot of training to react in the quickest way possible on all kinds of unforeseen events," he explained.

Two tiny CubeSats, miniaturized satellites for space research, are due to join the Hera mission to the asteroid system. The first CubeSat, the Asteroid Prospection Explorer (or 'APEX'), is due to perform detailed spectral measurements of the surfaces of the binary asteroid system, while the second, named Juventas, will measure the gravity field and the internal structure of Dimorphos.

Moissl said that there will be "some autonomous guidance and navigation capabilities" aboard Hera and the CubeSats.

"However, they cannot be classified as AI systems but rather very highly sophisticated computer programs," he explained.

The ESA scientist promised that the data from the mission will be made public as quickly as possible.

The agency's hope is that as many scientists from around the world take this data and work with it, regardless of where they come from or where they live, he concluded.